We interpret this as a cancellation of error between the self-interaction error and the overbinding of the O2 molecule in semilocal functionals. Inclusion of a U term in the electron Hamiltonian offers a convenient way for obtaining more precise geometric and electronic configurations of the defective systems.The potential of CeO2 as an epoxidation catalyst is studied for the reaction of propylene with hydrogen peroxide (H2O2) by Fourier transform infrared (FTIR) spectroscopy and temperature programmed desorption (TPD). Adsorption and decomposition of H2O2 and propylene oxide (PO) are also explored to determine their surface chemistry and thermal stability. Hydrogen peroxide adsorbed dissociatively on CeO2 forming adsorbed peroxo (O-O) species, as observed through vibrational features at 890 cm-1 and (830-855) cm-1 (FTIR). The signal at 890 cm-1 disappeared when a pulse of propylene was passed through the catalyst, and at the same time, adsorbed PO was observed (a sharp IR mode at 827 cm-1; ring deformation). The reaction between gas phase propylene and adsorbed peroxide species suggested the Eley-Rideal type mechanism. The absence of a ring opening reaction of PO at room temperature may indicate that CeO2 can be a suitable oxide for epoxidation of hydrocarbons. PO started to decompose above 323 K, as observed from FTIR and TPD results. TPD spectra of PO show its desorption at 365 K, with a small fraction decomposing into acetaldehyde and formaldehyde due to partial decomposition, while CO2 and CO are released at higher temperatures. Adsorbed acetate, formate, and carbonate species, formed due to further reactions of aldehydes, are observed during the thermal reaction (FTIR).The coordination reactions of 4-Azidobenzoic Acid (ABA) molecules on different active surfaces are studied by scanning tunneling microscopy and density functional theory calculations. ABA molecules deposited on Ag(111)/Ag(100)/Cu(100) held at room temperature lead to the decomposition of azide groups and the release of a N2 molecule per ABA molecule. Two residual segments of ABA molecules can interact with one Ag/Cu adatom to form a coordination dimer through the N-Ag/Cu-N coordination bond on different substrates. Different orientations with different symmetries can result in different nanostructures based on the dimers. Interestingly, the residual segments of ABA molecules can generate four Cu adatoms as the coordination center on Cu(100) to form a novel coordination complex after annealing, which is the first report for trapping four adatoms as a coordination center. The number and the species of adatoms captured can be changed to alter coordination structures. It expounds that various regulatory effects of different substrates lead to the diversity of nanostructures dominated by coordination bonds.The C2 carbon cluster is found in a large variety of environments including flames, electric discharges, and astrophysical media. Due to spin-selection rules, assessing a complete overview of the dense vibronic landscape of the C2 + cation starting from the ground electronic state X Σg+1 of the neutral is not possible, especially since the C2 + ground state is of X+?Σg-4 symmetry. In this work, a flow-tube reactor source is employed to generate the neutral C2 in a mixture of both the lowest singlet X Σg+1 and triplet a 3Πu electronic states. We have investigated the vibronic transitions in the vicinity of the first adiabatic ionization potential via one-photon ionization with vacuum ultraviolet synchrotron radiation coupled with electron/ion double imaging techniques. Using ab initio calculations and Franck-Condon simulations, three electronic transitions are identified and their adiabatic ionization energy is determined Ei(a+? 2Πu←X?1Σg +)=12.440(10) eV, Ei(X+? 4Σg -←a?3Πu)=11.795(10) eV, and Ei(a+2Πu ← a3Πu) = 12.361(10) eV. From the three origin bands, the following energy differences are extracted ΔE(a - X) = 0.079(10) eV and ΔE(a+ - X+) = 0.567(10) eV. The adiabatic ionization potential corresponding to the forbidden one-photon transition X+ ← X is derived and amounts to 11.873(10) eV, in very good agreement with the most recent measurement by Krechkivska et al. [J. Chem. Phys. 144, 144305 (2016)]. The enthalpy of formation of the doublet ground state C2 + cation in the gas phase is determined at 0 K, ΔfH0(0K)(C2 +(Πu2))=2019.9(10) kJ mol-1. In addition, we report the first experimental ion yield of C2 for which only a simple estimate was used up to now in the photochemistry models of astrophysical media due to the lack of experimental data.MoO3/γ-Al2O3 catalysts containing 0.3-3 monolayer (ML) equivalents of MoO3 were prepared, characterized, and tested for ethane oxidative dehydrogenation (ODH) in cyclic redox and co-feed modes. Submonolayer catalysts contain highly dispersed (2D) polymolybdate structures; a complete monolayer and bulk Al2(MoO4)3 are present at &gt;1ML loadings. High ethylene selectivity (&gt;90%) in chemical looping (CL) ODH correlates with Mo+VI to Mo+V reduction; COx selectivity is 1ML catalysts provide higher conversions albeit with 10%-18% lower selectivity and greater selectivity loss with increasing conversion. In co-feed mode, ethylene selectivity drops to less then 50% at 46% conversion for a 0.6ML catalyst, but selectivity is virtually unaltered for a 3ML catalyst. We infer that at less then 1ML loadings, small domain size and strong Mo-O-Al bonds decrease 2D polymolybdate reducibility and enhance ethylene selectivity in CL-ODH.In the past two decades, the density matrix renormalization group (DMRG) has emerged as an innovative new method in quantum chemistry relying on a theoretical framework very different from that of traditional electronic structure approaches. The development of the quantum chemical DMRG has been remarkably fast it has already become one of the reference approaches for large-scale multiconfigurational calculations. https://www.selleckchem.com/products/3-deazaneplanocin-a-dznep.html This perspective discusses the major features of DMRG, highlighting its strengths and weaknesses also in comparison with other novel approaches. The method is presented following its historical development, starting from its original formulation up to its most recent applications. Possible routes to recover dynamical correlation are discussed in detail. Emerging new fields of applications of DMRG are explored, such as its time-dependent formulation and the application to vibrational spectroscopy.